Magnetic seed technology for the efficient removal of nitrogen from wastewater

Abstract Nitrogen pollution is a global issue impacting ecosystems, climate change, human health, and the economy. The challenge to reduce nitrogen pollution as a priority highlights the wastewater treatment system an important point of control. Coagulation, a common water treatment process, has a positive impact on the overall treatment process but often struggles to address nitrogen pollution effectively. Our study introduces a novel magnetic seed to enhance coagulation in treating nitrogen pollution, offering a new solution for the global water treatment industry. We focus on the efficiency, mechanistic detail, and recovery potential of a magnetic zirconium tannate in treating real-world wastewater nitrogen under coagulation conditions. Results show that 9 g/L of magnetic zirconium tannate effectively removes ammonia nitrogen, organic nitrogen, and total nitrogen from five different wastewater types. For low-concentration wastewater with ammonia nitrogen below 20 mg/L and organic nitrogen below 5 mg/L, removal rates reach up to 100%. For high-concentration wastewater with ammonia nitrogen below 98 mg/L and organic nitrogen below 86 mg/L, the maximum removal rate is 59% for ammonia nitrogen and 88% for organic nitrogen. Spectral analysis reveals that magnetic zirconium tannate adsorbs nitrogen compounds in water through both hydrogen bonding and electrostatic interactions, achieving excellent treatment outcomes. It can be efficiently recovered without using complex organic eluents and is easily separated from the flocculate. This technology offers non-disruptive supplement for current treatment approaches to meet the global nitrogen pollution challenge head on.